The present invention relates generally to utility poles and, more particularly, to a plurality of pultruded segments adapted to be assembled to define a pole, such as a power pole and which may be assembled to encase a standing wooden pole.
A wooden utility pole of a type that is found in almost every rural and urban area is typically made from a tree that has been harvested from a forest. Either creosote, or a similar preservative, is usually applied to the wooden pole to prevent rotting due to insect infestation. It should be understood that creosote is a carcinogen.
Electric power as well as video and telephone signals are typically transmitted via a wire supported by a plurality of wooden utility poles. Historically, there has been an increasing demand for the electric power as well as television and telephone service that has caused an increased use of the wooden poles. A result of the increased use has been a correspondingly increased harvesting of trees that has caused an environmentally undesirable deforestation. Therefore, it is desirable to use materials, other than wood, from which to make a utility pole.
U.S. Pat. No. 5,513,477 to Farber, for example, discloses a hollow utility pole that is formed from a plurality of similar segments of a fiber/resin composite. The thickness of the segments is minimized to correspondingly minimize the weight of the segments.
The composite utility pole is formed by bonding together a side face of one segment to a side face of the other segment about a hollow inner tube, the length and wall thickness of which varies according to the desired strength and stiffness properties. External, molded, reinforcing members are adhesively bonded to the exterior of the inner tube. It should be appreciated that the side faces have a width that substantially equals the thickness of the segments. Because of the minimized thickness, the bonding may not be over an area large enough to provide adhesion necessary for the composite pole to withstand environmentally induced structural stresses due to adverse weather conditions for example. Further the molded outer segments, because of the size of the molds, may require that the segments be stacked and adhesively bonded along the length of the reinforced tube. Thus the technique of this reference typically requires production of the inner tube, which could be pultruded, molding the outer segments and bonding the elements together.
In Kelsey, U.S. Pat. No. 4,803,819 discloses a pultruded power pole of a one piece construction which includes internal, reinforcing, struts. The one piece construction may, due to weight, preclude shipment along roadways or use in some situations.
When an old wooden utility pole is removed and replaced, it is preferably disposed of in an economically feasible manner with a reduced probability that the carcinogenic creosote in the old pole will seep into the ground and groundwater supply. Hence, old wooden pole may be required to be disposed of at an appropriate toxic disposal site. The cost of the disposal of the removed wooden pole increases the cost of replacement and also imposes a societal cost of constructing and maintaining toxic disposal sites.
Heretofore, there has not been a suggestion in the prior art of a utility pole made from connected non-wooden segments that can reliably withstand the environmentally induced structural stresses. Additionally, the prior art is silent as to how to avoid removal and replacement of deteriorated wooden poles in such a manner as to avoid disposal costs and the filling of toxic disposal sites with wooden poles.
There is provided, according to one aspect of the present invention, a pole which is produced by assembling, in situ, a plurality of pultruded segments each having a longitudinal length corresponding to the desire length of the pole. Each segment has longitudinally extending edges including male and female couplers to mechanically couple the segments together to define the pole. Preferably, the male and female couplers have a constant diametrical cross-section to be consistent with pultrusion.
In another aspect, a method is set forth which includes assembling the pole according to the present invention about a standing wooden pole to re-enforce and encase the pole.